Remove unnecessary code (#9303)

Motivation:

There are is some unnecessary code (like toString() calls) which can be cleaned up.

Modifications:

- Remove not needed toString() calls
- Simplify subString(...) calls
- Remove some explicit casts when not needed.

Result:

Cleaner code

codec-http/src/test/java/io/netty/handler/codec/http/CombinedHttpHeadersTest.java

@@ -55,7 +55,7 @@ public class CombinedHttpHeadersTest {
         otherHeaders.add(HEADER_NAME, "a");
         otherHeaders.add(HEADER_NAME, "b");
         headers.add(otherHeaders);
-        assertEquals("a,b", headers.get(HEADER_NAME).toString());
+        assertEquals("a,b", headers.get(HEADER_NAME));
     }
 
     @Test
@@ -66,7 +66,7 @@ public class CombinedHttpHeadersTest {
         otherHeaders.add(HEADER_NAME, "b");
         otherHeaders.add(HEADER_NAME, "c");
         headers.add(otherHeaders);
-        assertEquals("a,b,c", headers.get(HEADER_NAME).toString());
+        assertEquals("a,b,c", headers.get(HEADER_NAME));
     }
 
     @Test
@@ -99,7 +99,7 @@ public class CombinedHttpHeadersTest {
         otherHeaders.add(HEADER_NAME, "b");
         otherHeaders.add(HEADER_NAME, "c");
         headers.set(otherHeaders);
-        assertEquals("b,c", headers.get(HEADER_NAME).toString());
+        assertEquals("b,c", headers.get(HEADER_NAME));
     }
 
     @Test
@@ -110,7 +110,7 @@ public class CombinedHttpHeadersTest {
         otherHeaders.add(HEADER_NAME, "b");
         otherHeaders.add(HEADER_NAME, "c");
         headers.add(otherHeaders);
-        assertEquals("a,b,c", headers.get(HEADER_NAME).toString());
+        assertEquals("a,b,c", headers.get(HEADER_NAME));
     }
 
     @Test
@@ -121,7 +121,7 @@ public class CombinedHttpHeadersTest {
         otherHeaders.add(HEADER_NAME, "b");
         otherHeaders.add(HEADER_NAME, "c");
         headers.set(otherHeaders);
-        assertEquals("b,c", headers.get(HEADER_NAME).toString());
+        assertEquals("b,c", headers.get(HEADER_NAME));
     }
 
     @Test

codec-http/src/test/java/io/netty/handler/codec/http/HttpContentCompressorTest.java

@@ -272,7 +272,7 @@ public class HttpContentCompressorTest {
         assertEncodedResponse(ch);
 
         ch.writeOutbound(LastHttpContent.EMPTY_LAST_CONTENT);
-        HttpContent chunk = (HttpContent) ch.readOutbound();
+        HttpContent chunk = ch.readOutbound();
         assertThat(ByteBufUtil.hexDump(chunk.content()), is("1f8b080000000000000003000000000000000000"));
         assertThat(chunk, is(instanceOf(HttpContent.class)));
         chunk.release();
@@ -423,7 +423,7 @@ public class HttpContentCompressorTest {
         res.headers().set(HttpHeaderNames.CONTENT_ENCODING, HttpHeaderValues.IDENTITY);
         assertTrue(ch.writeOutbound(res));
 
-        FullHttpResponse response = (FullHttpResponse) ch.readOutbound();
+        FullHttpResponse response = ch.readOutbound();
         assertEquals(String.valueOf(len), response.headers().get(HttpHeaderNames.CONTENT_LENGTH));
         assertEquals(HttpHeaderValues.IDENTITY.toString(), response.headers().get(HttpHeaderNames.CONTENT_ENCODING));
         assertEquals("Hello, World", response.content().toString(CharsetUtil.US_ASCII));
@@ -445,7 +445,7 @@ public class HttpContentCompressorTest {
         res.headers().set(HttpHeaderNames.CONTENT_ENCODING, "ascii");
         assertTrue(ch.writeOutbound(res));
 
-        FullHttpResponse response = (FullHttpResponse) ch.readOutbound();
+        FullHttpResponse response = ch.readOutbound();
         assertEquals(String.valueOf(len), response.headers().get(HttpHeaderNames.CONTENT_LENGTH));
         assertEquals("ascii", response.headers().get(HttpHeaderNames.CONTENT_ENCODING));
         assertEquals("Hello, World", response.content().toString(CharsetUtil.US_ASCII));

codec-xml/src/main/java/io/netty/handler/codec/xml/XmlDecoder.java

@@ -39,7 +39,7 @@ public class XmlDecoder extends ByteToMessageDecoder {
     private static final XmlDocumentEnd XML_DOCUMENT_END = XmlDocumentEnd.INSTANCE;
 
     private final AsyncXMLStreamReader<AsyncByteArrayFeeder> streamReader = XML_INPUT_FACTORY.createAsyncForByteArray();
-    private final AsyncByteArrayFeeder streamFeeder = (AsyncByteArrayFeeder) streamReader.getInputFeeder();
+    private final AsyncByteArrayFeeder streamFeeder = streamReader.getInputFeeder();
 
     @Override
     protected void decode(ChannelHandlerContext ctx, ByteBuf in, List<Object> out) throws Exception {

codec/src/test/java/io/netty/handler/codec/ByteToMessageCodecTest.java

@@ -64,7 +64,7 @@ public class ByteToMessageCodecTest {
         assertTrue(ch.finish());
         assertEquals(1, (int) ch.readInbound());
 
-        ByteBuf buf = (ByteBuf) ch.readInbound();
+        ByteBuf buf = ch.readInbound();
         assertEquals(Unpooled.wrappedBuffer(new byte[]{'0'}), buf);
         buf.release();
         assertNull(ch.readInbound());

common/src/main/java/io/netty/util/NetUtil.java

@@ -319,7 +319,7 @@ public final class NetUtil {
                 if (line.startsWith(sysctlKey)) {
                     for (int i = line.length() - 1; i > sysctlKey.length(); --i) {
                         if (!Character.isDigit(line.charAt(i))) {
-                            return Integer.valueOf(line.substring(i + 1, line.length()));
+                            return Integer.valueOf(line.substring(i + 1));
                         }
                     }
                 }

common/src/main/java/io/netty/util/internal/PlatformDependent.java

@@ -1102,8 +1102,8 @@ public final class PlatformDependent {
 
         // Last resort: guess from VM name and then fall back to most common 64-bit mode.
         String vm = SystemPropertyUtil.get("java.vm.name", "").toLowerCase(Locale.US);
-        Pattern BIT_PATTERN = Pattern.compile("([1-9][0-9]+)-?bit");
+        Pattern bitPattern = Pattern.compile("([1-9][0-9]+)-?bit");
-        Matcher m = BIT_PATTERN.matcher(vm);
+        Matcher m = bitPattern.matcher(vm);
         if (m.find()) {
             return Integer.parseInt(m.group(1));
         } else {